Water-in-oil emulsion lubricants



Uflit I;

2,894,910 WATER-TlN-OIL EMULSION LUBRICANTS No Drawing. Application July 23, 1956 Serial No. 599,329

Claims. (Cl. 25242.7)

This invention relates to improved emulsion lubricants and hydraulic fluids. More particularly it pertains to water-in-oil emulsion lubricants especially useful for slow speed diesel engines and as fire-resistant hydraulic fluids which possess good lubricating properties and which are stable, non-corrosive and Wear-resistant.

Although it is known in the art that certain emulsions are useful as coolants and lubricants in metal working operations and as rust and corrosion inhibitors, their use as engine lubricants and as hydraulic fluids has been limited. Under engine operating conditions, emulsions generally lack desired lubricity, cause wear and corrosion.

Fluid compositions for use in many hydraulic systems should be fire-resistant, non-corrosive, thermally stable and resistant to oxidation. Hydraulic fluids such as mineral oils or other organic fluids such as castor oil, esters of carboxylic acids, organic phosphates, glycols and their derivatives, silicone polymers, chlorinated or fluorinated organic materials as well as aqueous solutions, lack one or more desired properties which such fluids should possess. Thus, mineral oils are highly flammable, castor oil results in sludge and gum formation, esters of carboxylic acids cause swelling of rubber, the organic phosphates and the glycols are corrosive, the halogen-containing materials tend to hydrolyze, while the silicone compounds lack lubricity and present a health hazard.

It is an object of this invention to provide an emulsion lubricant and fire resistant hydraulic fluid having good lubricating properties. Another object is to provide a composition which is a satisfactory lubricant for low speed diesel engines and hydraulic equipment, which is stable, fire-resistant, resistant to deterioration, inhibits corrosion and does not cause wear. Still another object of this invention is to provide an emulsion lubricant and fire-resistant hydraulic fluid of good lubricating quality even when subjected to various adverse conditions of temperature, loads and speeds as encountered in various diesel engines operating on high sulfur fuels or in certain hydraulic systems.

These and other objects are accomplished in accordance with this invention by providing a composition comprising a water-in-oil emulsion in which the water phase is from 20% to 45% and the oil phase is from 55% to 80% of the emulsion, said emulsion containing a combination of minor amounts each of two essential additives one of which is an oil-soluble polyvalent metal phenate and the other is an oil-soluble high molecular weight alkane- .polyol. They may be obtained as polymeric compounds by substantially completely hydrolyzing a copolymer of a long chain alpha olefinic hydrocarbon (normal or branched-chain) containing a terminal -CH=CH group, and containing at least carbon atoms, and a vinyl ester of a lower fatty acid having up to five carbon atoms, such as vinyl acetate, vinyl propionate, vinyl isobutyrate, or vinyl isovalerate. The final product is a macromolecular organic compound containing essentially a plurality of recurring alkyl-1,2-ethylene and hydroxy- 1,2-ethylene units joined together in a chain-like manner,

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wherein the alkyl radicals contain at least 8 carton atoms. There may be a minor proportion of alkanoyloxy-1,2- ethylene (from unhydrolyzed ester groups) units as essentially the only other polar-containing group. The ratio of the non-acidic oxygen containing units (hydroxyland alkanoyloxy-) 1,2-ethylene to the alkyl-1,2-ethylene units is from about 1 to about 5 and the average molecular weight of the final product is from about 4,000 to about 50,000. The non-acidic oxygen-containing polar groups present in the final product are predominantly hydroxyl, being at least hydroxyl, preferably at least or as high as 99% of the non-acidic oxygen-containing polar groups.

The oil-soluble phenates which are effective in combination with the higher alkane polyols water-in-oil emulsions of this invention include those described in United States Patents 2,197,833, 2,228,654, 2,280,419, 2,344,988, 2,361,804, 2,410,652, 2,501,991, 2,501,992 and 2,610,982. Specifically, they can be either simple phenates, such as metal alkylphenates (Ca cetylphenate), polar substituted simple phenates (Ca or Zn alkyl salicylates) or polyphenates, such as where a plurality of the simple phenates are condensed at positions ortho and/ or para to the phenolic hydroxy group through alkylidene (cg. methylene) radicals or other suitable divalent non-metallic radicals, such as sulfur or selenium. Although various metal phenates are contemplated in the practice of the invention including monoand polyvalent metal phenates," such as the alkali, alkaline earth and heavy metal phenates, of which the preferred ones are the polyvalent metal phenates of the metals of group II of the periodic table and having an atomic number of from 12 to 5 6, especially the alkaline earth metals within that group of metals. Illustrative compounds are: Na, K, Li, Ca, Ba, Sr, Mg, Zn, Al, Cd, Ni, Fe, Co cetylphenate, dibutylphenate, (E -C alkyl salicylate, waxylphenate, cyclohexylphenate, octylthiophenate, cetylthiophenate as well as the above metal salts of the condensation product of alkyl phenol with formaldehyde, acetaldehyde, furfuraldehyde or benzaldehyde, e.g., Ca, Ba, or Mg salts of octyl phenolformaldehyde condensation product ranging in molecular weight of from 400 to 1,100.

'The oil-soluble phenates are eifective in the emulsions in amounts of from about 0.01% to about 10%, the amount preferably being from about 0.1% to about 5% by weight.

In the polymeric material broadly described it is believed that the polar-containing and non-polar units are substantially uniformly distributed throughout the length of the hydrocarbon chain in accordance with the respective molecular proportions of the olefin and ester monomers utilized in the preparation with some randomness from exact regularity. Furthermore, even where two polar containing ethylene units are bound directly, the polar groups in general are attached to nonadjacent carbon atoms.

The alpha olefins suitable to form the copolymers include olefins having a single terminal ethylenic group and containing from 10 to 40 carbon atoms and preferably from 12 to 30 carbon atoms such as a-decene, a-hexadecene, ot-tetradecene, a-pentadecene, a-heptadecene, aoctadecene, a-nonadecene, a-eicosene, a-docosene, a-triacontene, and mixtures thereof. Mixtures of a-olefins containing from 12 to 20, and preferably 16 to 18 carbon atoms obtained by pyrolysis of paraflin waxes, are particularly suitable and represent a readily available economic material.

The unsaturated esters which are useful to make the copolymer are exemplified by vinyl esters of lower saturated fatty acids, such as vinyl acetate, vinyl propionate, vinyl butyrate, vinyl isovalerate, and mixtures thereof.

Normally, these reactants are copolymerized in the presence of a catalyst. Catalysts which are suitable for the copolymerization include various organic peroxides, such as aliphatic, aromatic, heterocyclic, and alicyclic peroxides such as diethyl peroxide, tertiary butyl hydro- 4 with stirring and about 0.3% w. of di-tert-butyl peroxide was added and the mixture heated for about 5 hours. An amount of vinyl acetate equal to that charged was added to the mixture at such a rate that the vinyl aceperoxide, dibenzoyl peroxide, dimethylthienyl peroxide, 5 tate/olefin ratio in the unreacted vinyl acetate to olefin dicyclohexyl peroxide, dilauroyl peroxide, di-tert-butyl was around 2.5. After 5 hours of heating the reaction peroxide, and urea peroxide. These specific peroxides mixture was topped to remove unreactecl vinyl acetate are mentioned by way of nonlimiting examples of suitable and peroxide decomposition products. About 97% of organic peroxides. the polymerizable olefins were converted to polymer.

The identity and proportion of catalyst selected and the The polymer was alcoholized by refluxing it for about temperature employed in the copolymerization can be two hours with a mixture of methanol and aromatic solvaried to produce products having difierent molecular vent containing a small amount of sodium methoxide. weights as desired. Thus, if one desires lower molecular To this was added a mixture of aromatic solvent and weight products, one might select a higher reaction temwater and the entire mixture was shaken, allowed to sepperature, such as of the order of 150 C. to 300 C., arate into layers at 5060 C. and the upper phase was and select a catalyst that has a satisfactory decomposition removed, The material was then heated to 125 C. to rate within that range of temperature. When a higher remove residual methanol, methyl acetate and water. molecular weight product is desired, a lower tempera- The aromatic solvent can be removed by stripping at a ture range may be used, such as 50 C. to 150 C., and temperature of 180 C. at 1 mm. The ratio of vinyl a catalyst having a satisfactory decomposition rate within acetate to l fi i th polymer was around 4 85 d that range may be elected. In general, it is preferred to the molecular weight ranged around 30,000 to 35,000. employ temperatures within the range of 80 C. to 200 C. and catalysts which are efiective within that range. EXAMPLE IA The polymerization may be conducted in the presence moles of vinyl acetate and 1 mole of a mixture or absence of air. In most cases, however, it has been 25 of C to C alpha olcfins, predommautly C olefins, found desirable to conduct the polymerization in the and 1% ditertrary butyl perox1de were placed in a stainabsence of air, e.g., in the presence of an inert gas such less steel bomb and the air replaced with nitrogen. The as nitrogen. Atmospheric, reduced, or superatmospheric bomb was heated to 115 C. until there was about 90% pressure may be employed. conversion. The product was topped at 185 C. at 1 At the end of the polymerization, unreacted monomer mm. Hg pressure. is removed, usually suitably by distillation. The polymer product was then mixed with methanol The conversion of the ester groups to hydroxyl groups and sodium methylate so as to efiect a 95% conversionn can be accomplished by hydrolysis or alcoholysis. Hyof the acetate groups to hydroxyl groups. This Was acdrolysis or alcoholysis can be accomplished by the methcomplished by adding 10 parts of methanol, parts of ods described in Us. Patent 2,421,971. Hydrolysis may 35 isopropyl alcohol and 1 part of sodium methylate per be by saponification, with aqueous alkali, such as sodium 50 parts of the copolymer and neutralizing with stirring hydroxide, or by alcoholysis reaction wherein the cofor 8 hours at 70 C. Sodium acetate was then removed polymer is treated with a lower Water-soluble alkanol, by washing twice with 1 part of a 33% isopropyl alcohole.g. methyl, ethyl or isopropyl alcohol, or mixture of a water mixture. After settling, the lower layer was drained lower alkanol and a suitable base catalyst, such as so- OE and all low boiling components stripped ofi at a temdium ethoxide. t perature of 110 C. at 90 mm. Hg. The resulting co- After the saponification or alcoholysis, the mixture is polymer w s a ticky yello solid, treated to remove materials other than the desired prod- An 81 not, such as by distillation to remove volatile materials ratio of acetate ms alcoh 1 t and by water-soluble salt impurities, such as sodium acelefin C alk rou 0 groups 0 5/1 ta te. It is particularly important to remove water-soluble Wt 14 16 y g PS 2700 salts in order to obtain copolymers which can be used 3 fiS' h drOX 1 t t t 19/ as additives for fuel oils without forming undesirable y y o ace ae 1 haze. Following essentially the procedure of Example I, other The following examples are given as illustrative of products were prepared as Examples II through XXI in suitableproducts and their preparation. accordance with the following tabulation showing the polymerization catalyst, polymerization temperature, ratio EXAMPLE I of vinyl ester to olefin used and ratio in the product, de- About 21.8 moles of G -C OC-OIGfiHS and 54.4 moles gree of hydrolysis of the ester groups and average molecuof undistilled vinyl acetate were heated to about 140 C. lar weight.

Tempera- Vinyl Acetate/a-Olefin Ratio in Vinyl Acetate/ Degree of Example Catalyst ture, O. Polymer a-Olefin Ratio Hydrol- Mol Wt.

in Polymer ysis II ditertiarybutyl peroxide 115 5 92 27,000 TTT do 115 2. 6 95 11,000 115 2 95 8,000 130 4.9 92 20,000 140 o 5 95 20,000 140 4.0/1(Ci0Cis Olefin) 4. 9 90 30, 000 80 1.6/1(octadecene) 3. 6 95 16, 500 80 2/1(oetadecene) 4. O6 97 20, 000 110 do 3.4 88 8,330 80 do 1.52 95 5,120 80 d0 1.72 95 5,710 80 2 5/1 (octadecene)- 4.1 95 20,100 80 2/1 (octadecene) 3. 89 97 14, 200 115 3/1 (octadecene) 4. 1 90 11, 000 80 2/1(dodecene) 2. 6 90 8, 000 80 2/l(hexadecene) 3. 1 90 8,000 o 2.14 90 16,400 2/1(vinylbutyratea/a-octadecene) 2. 1 8, 000 80 1/1.2(octadecene) l 8, 000 80 1/1.2 (hexadecene) 1 95 8, 000

1 Mol wt. determined by light scattering technique described in Chem. Ttes, vol. 40, p 139 (1948).

The polymers are efiective when used in amounts of from about 1% to about by weight and preferably from about 1.5 to about 5% by weight, based on the total composition.

The aqueous phase of the water-in-oil emulsion should range from about to about 45% and preferably from about to about by weight of the emulsion. The oil phase can vary from about to about 80% and preferably from about to about of the emulsion. The oil may be entirely a hydrocarbon oil of wide viscosity range, e.g., from less than 50 SUS at 100 F. to 150 SUS at 210 F.

Oils of this type can be obtained from various crudes such as paraflinic, naphthenic or mixed base crudes; refined oils in the lubricating oil viscosity range are preferred. On the other hand, the hydrocarbon oil may be blended with fixed oils such as castor oil, lard oil and the like, and/or with synthetic lubricant such as polymerized olefins, organic esters of organic and inorganic acids, e.g., di-Z-ethylhexyl sebacate, dioctyl phthalate, trioctyl phosphate; polymeric tetra-hydrofuran, polyalkyl silicone polymer, e.g., dimethyl silicone polymer and the like. Where mixtures or blends are used the hydrocarbon oil such as a mineral lubricating oil is always present in the predominant amount such as from about 60% to about of the oil blend. A straight mineral lubricating oil, having a viscosity index of at least 50 and ranging in viscosity at F. of from 75 to 200 SUS, is usually preferred.

6 and the alkane polyol, while constantly stirring the mixture.' rHeating the emulsion during or after it is prepared is not neccessary. If desired, the emulsion can be homogenized to insure a homogeneous composition.

A composition (A) of this invention was prepared by slowly adding 40% water into a vessel containing 60% of a refined mineral oil of 150 SUS viscosity at 100 F, and containing 1.5% polymer of Example I and 4% of Ca salt of octyl phenol-formaldehyde condensation product, while constantly stirring the mixture. The entire mixture was transferred to a homogenizer where it was agitated for about 5 minutes until a homogeneous waterin-oil emulsion was formed. Compositions (B), (C) and (D) were prepared in a similar manner except that the products of Example IA, V11 and VIII were used in place of the alkane polyol of Composition (A).

Other examples of this invention include a water-in-oil emulsion containing from 1% to 5% of polymers of Example I, 111, V, VII or VIII and from 1% to 10% of calcium or barium (neutral or basic) cetyl phenate alkylsalicylate and the like.

The outstanding properties of hydraulic fiuids of this invention with respect to stability and fire-resistance are shown in Table I. The stability test is determined by determining the amount of separation of tree oil, cream and water at both room temperature and F. from a 100 ml. test sample. The fire-resistance was determined by the pipe cleaner test described in Lubrication Engineering, March-April 1955, pages 86-87.

Table l.-Emulsl0n stabllzty test Room Temperature Percent 140 F. Percent Percent Water Percent Cream Water Composition Days Percent Percent Separa- Days Oil Separa- Separa- Oil Cream tion (ca) Separation (00.) tlon (00.) Separa- Separation (00.) tion (0a.) tion (cc.)

A 62 2 0 Trace 13 5 0 1 B 62 2 0 Trace 13 5 0 1 C 62 2 0 Trace 13 5 0 1 D 62 2 0 Trace 13 5 O 1 Water/oil emulsion (40/60) containing 1.5% Ex.

VII additive 62 50 0 10 3 8 10 3 Water/oil emulsion (40/60) containing 4% Ca salt of octyl phenol formaldehyde condensation pr duct Water/011 emulsion (40/60) containing 1.5% additive of Ex. VII and 8% Ca petroleum sulfonate. 13 Trace 30 0 2 1 10 Trace Water/oil emulsion (40/60) containing 1.5% additive of Ex. VII and 1% glycerol monooleate 37 1 38 Trace 7 1 48 12 Water/oil emulsion (40/60) containing 1.5% additive of Ex. VII and 5% octadecylamine 24 2 29 Trace 7 1 32 2 Water/oil emulsion (40/60) containing 1% alkyl phenoxyethylene ethanol (Igepal DM-710 made by Antara Chemicals Division of General Aniline and Film Corp) 5 5 1 70 3 Water/oil emulsion (40/60) containing copolymer of vinyl pyridine/lauryl methaerylate Water/oil emulsion (40/60) containing copolymer of vinyl pyrrolidone/lauryl methaerylate Water/oil emulsion (40/60) containing copolymer of lauryl methacrylate/diethylamine ethyl methacrylate 1 Complete phase separation. 2 Complete phase.

Compositions of this invention can be modified by addition thereto of minor amounts (0.01-12%) of optional additives such as corrosion inhibitors, stabilizers, anti- Wear agents, and the like, but which do not interfere with the essential additives of this invention and which are compatible with the emulsion without materially altering the stability and other properties of the emulsion. Included among such materials are inorganic and organic salts such as water-soluble polyvalent metal salts such as calcium, barium or magnesium nitrite, nitrate, sulfate, chloride, chromate, formate, acetate and the like.

Compositions of this invention are readily prepared. No special equipment or technique is necessary in the preparation of them. A preferred method is to add the required amount of water to the oil containing the phenate In the pipe cleaner test, Compositions A through D passed over 50 cycles while mineral oil or mineral oil containing 4% of Ca petroleum sulfonates and/or Ca salt of octylphenol-formaldehyde condensation product ignited after about 5 cycles.

Compositions of this invention are particularly suitable for use in diesel engines, in die casting machines, in permanent mold machines in steel mill equipment such as coke pushers, pipe coupling tighteners, combustion control mechanisms, plastic molding presses and glass blowing machines and the like.

We claim as our invention.

1. A lubricant and hydraulic fluid consisting essentially of a water-in-oil emulsion in which the water phase constitutes from about 30 to about 40% of the emulsion and the oil phase constitutes from about 70% to about 60% of the emulsion, said emulsion containing from about 1 to about 10% by weight of hydrolyzed copolymer of a hydrocarbon a-olefin containing from 10 to 40 carbon atoms and a vinyl ester of a lower fatty acid having up to 5 carbon atoms in the mol ratio of from 1/1 to 1/5, respectively and having a molecular Weight of from 4,000 to 50,000 and from about 0.01% to about of an oil soluble polyvalent metal C alkyl phenate of the metal of group II of the periodic table having an atomic number of from 12 to 56.

2. The composition or" claim 1, wherein the metal phenate is an alkaline earth metal C alkyl phenate and the hydrolyzed copolymer is a copolymer of an tat-olefin containing from 12 to carbon atoms and a vinyl ester of a lower fatty acid of up to 5 carbon atoms.

3. The composition of claim 1, wherein the polyvalent metal phenate is calcium C alkyl phenate and the copolymeris a hydrolyzed copolymer of a C1648 ot-olefin and vinyl acetate.

4. A lubricant and hydraulic fluid consisting essentially of a water-in-oil emulsion in which the water phase constitutes about of the emulsion and the oil phase is of the emulsion, said emulsion containing about 0.1 to about 5% by weight calcium salt of octylphenolformaldehyde condensation product and from about 1.5 to about 5% by weight of a hydrolyzed copolymer of a C hydrocarbon ot-olefin and vinyl acetate in the mol ratio of from 1/1 to 1/5, respectively and having a molecular weight of from 4,000 to 50,000.

5. The composition of claim 4, wherein the olefin and vinyl acetate constituents in the polymer are in the ratio of from 1:2 to 1:4, respectively.

References Cited in the file of this patent UNITED STATES PATENTS 2,421,971 Sperati June 10, 1947 2,551,643 Seger et al May 8, 1951 2,744,870 Stillebroer et a1 May 8, 1956 2,800,453 Bondi July 23, 1957 

1. A LUBRICANT AND HYDRAULIC FLUID CONSISTING ESSENTIALLY OF A WATER-IN-OIL EMULSION IN WHICH THE WATER PHASE CONSTITUTES FROM ABOUT 30 TO ABOUT 40% OF THE EMULSION AND THE OIL PHASE CONSTITUTES FROM ABOUT 70% TO ABOUT 60% OF THE EMULSION, SAID EMULSION CONTAINING FROM ABOUT 1 TO ABOUT 10% BY WEIGHT OF HYDROLYZED COPOLYMER OF A HYDROCARBON A-OLEFIN CONTAINING FROM 10 TO 40 CARBON ATOMS AND A VINYL ESTER OF A LOWER FATTY ACID HAVING UP TO 5 CARBON ATOMS IN THE MOL RATIO OF FROM 1/1 TO 1/5, RESPECTIVELY AND HAVING A MOLECULAR WEIGHT OF FROM 4,000 TO 50,000 AND FROM ABOUT 0.01% TO ABOUT 10% OF AN OIL SOLUBLE POLYVALENT METAL C8-18 ALKYL PHENATE OF THE METAL OF GROUP II OF THE PERIODIC TABLE HAVING AN ATOMIC NUMBER OF FROM 12 TO
 56. 